// ASM: a very small and fast Java bytecode manipulation framework
// Copyright (c) 2000-2011 INRIA, France Telecom
// All rights reserved.
//
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// modification, are permitted provided that the following conditions
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//    notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.
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//    contributors may be used to endorse or promote products derived from
//    this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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package org.objectweb.asm.tree.analysis;

import java.util.Set;
import org.objectweb.asm.tree.AbstractInsnNode;

/**
 * A {@link Value} which keeps track of the bytecode instructions that can produce it.
 *
 * @author Eric Bruneton
 */
public class SourceValue implements Value {

	/**
	 * The size of this value, in 32 bits words. This size is 1 for byte, boolean, char, short, int, float, object and array types, and 2 for long and double.
	 */
	public final int size;

	/**
	 * The instructions that can produce this value. For example, for the Java code below, the instructions that can produce the value of {@code i} at line 5 are the two ISTORE instructions at line 1 and 3:
	 *
	 * <pre>
	 * 1: i = 0;
	 * 2: if (...) {
	 * 3:   i = 1;
	 * 4: }
	 * 5: return i;
	 * </pre>
	 */
	public final Set<AbstractInsnNode> insns;

	/**
	 * Constructs a new {@link SourceValue}.
	 *
	 * @param size
	 *          the size of this value, in 32 bits words. This size is 1 for byte, boolean, char, short, int, float, object and array types, and 2 for long and double.
	 */
	public SourceValue(final int size) {
		this(size, new SmallSet<AbstractInsnNode>());
	}

	/**
	 * Constructs a new {@link SourceValue}.
	 *
	 * @param size
	 *          the size of this value, in 32 bits words. This size is 1 for byte, boolean, char, short, int, float, object and array types, and 2 for long and double.
	 * @param insnNode
	 *          an instruction that can produce this value.
	 */
	public SourceValue(final int size, final AbstractInsnNode insnNode) {
		this.size = size;
		this.insns = new SmallSet<>(insnNode);
	}

	/**
	 * Constructs a new {@link SourceValue}.
	 *
	 * @param size
	 *          the size of this value, in 32 bits words. This size is 1 for byte, boolean, char, short, int, float, object and array types, and 2 for long and double.
	 * @param insnSet
	 *          the instructions that can produce this value.
	 */
	public SourceValue(final int size, final Set<AbstractInsnNode> insnSet) {
		this.size = size;
		this.insns = insnSet;
	}

	/**
	 * Returns the size of this value.
	 *
	 * @return the size of this value, in 32 bits words. This size is 1 for byte, boolean, char, short, int, float, object and array types, and 2 for long and double.
	 */
	@Override
	public int getSize() {
		return size;
	}

	@Override
	public boolean equals(final Object value) {
		if (!(value instanceof SourceValue)) {
			return false;
		}
		SourceValue sourceValue = (SourceValue) value;
		return size == sourceValue.size && insns.equals(sourceValue.insns);
	}

	@Override
	public int hashCode() {
		return insns.hashCode();
	}
}
